Pressing play on a CD normally feels like starting at the beginning. On some discs, however, audio exists before the nominal start of track one. That material may be a hidden song, an introduction or an interlude rather than a separately numbered track.
The CUETools documentation on pregaps explains this area and its relationship to hidden track-one audio. It also makes an important distinction for listeners: the presence of a pregap does not itself prove that a secret song is there. It may contain silence.
Check the edition before looking for a missing track
An album title can refer to different releases with different layouts. A later CD pressing, a digital download and a streaming edition need not reproduce the same sequence or extra material. Note the edition and catalogue details before assuming one copy is incomplete.
On players that support the relevant navigation, hidden audio may be reached by scanning backwards from the beginning of track one. Behaviour depends on the player and disc. Follow the equipment’s controls; repeatedly pressing “previous track” is not necessarily the same operation.
Describe what you actually hear
For a listening note, record the disc edition, player and the point at which sound becomes audible. Separate an observation such as “an introduction plays before the displayed start of track one” from a claim about why the artist placed it there.
If you are cataloguing a personal collection, consult the release documentation and the software’s treatment of gaps. Do not assume that a list of extracted track files preserves every boundary or piece of audio from the disc.
A small detail can change the opening
Try listening to the opening sequence as presented by the edition you own, then compare its published track information. The interest lies in how the release is arranged, not in declaring one format universally superior.
Hidden pregap audio is a reminder that an album is also a physical and technical object. Its beginning can be less obvious than the first number on the display.